1. Field of the Invention
This invention relates to a plate cylinder for a printing press including a forward and a rearward tensioning rail equipped with tensioning elements for tensioning a printing plate in contact with the circumference of the plate cylinder at the beginning and end of printing, with the tensioning rails being disposed in a trough extending axially along the circumference of the plate cylinder and having a forward and a rearward trough wall.
2. Description of the Prior Art
During printing on a printing press, the problem may arise that the printed image of one color is canted or tilted so to speak, relative to the printed image of another color. This canting must of course be eliminated to prevent the printed sheets from being wasted paper.
For this purpose it is known to unilaterally displace the axis of the respective plate cylinder. However, this only inaccurately compensates for the respective printing unit being out of register.
For the same purpose it is also known to offset the tensioning rails axially. However, this is complicated from a structural point of view and the friction between the actual plate cylinder and the printing plate must be overcome. In this connection, it should be brought to mind that a printing plate cannot be stressed with forces of any desired magnitude because it would be unduly deformed.